1. Field of the Invention
The present invention relates to a connector terminal and an inter-connecting terminal and more particularly to a terminal provided with a core wire-fixing barrel in which two or more electric wires are inserted and crimped on the wires to contact with the wires and fix them, and for reducing the contact resistance between electric wires in fixing two or more electric wires thereto by a barrel and between the wires and the terminal.
2. Description of the Related Art
A connector terminal to be used to connect electric wires of a wire harness of an automobile or electric office automation equipment has a construction as shown in FIG. 10. An inter-connector terminal or an intermediate joint terminal for connecting electric wires without the intermediary of a connector has a construction as shown in FIG. 13.
That is, the connector terminal 1 which is solid comprises an electrical contact portion 3 disposed in the front of a bottom 2 and a core wire-fixing barrel 4 and a coating film-fixing barrel 5 both disposed in the rear of the bottom 2. The inter-connecting terminal 6, which is U-shaped in its sectional configuration, consists of only a core wire-fixing barrel 7.
A W-type fixing method, a C-type fixing method or an F-type fixing method, soldering or welding is used to connect the electric wires to the connector terminal 1 or the interconnecting terminal 6. The F-type fixing method is most widely used because this method is the most efficient of these methods.
As shown in FIGS. 15 and 16, according to F-type fixing method, in fixing two electric wires W1 and W2 to the inter-connecting terminal 6, the inter-connecting terminal 6 is placed on an anvil 11 of a presser 10. The core wire 8 of the electric wire W1 and the core wire 8' of electric wire W2 are inserted into the core wire-fixing barrel 4 with the core wire 8 held in a higher space and the core wire 8' held in a lower space. Then, a crimper 12 is moved downwardly to deform the barrel 7 and fix the core wires 8 and 8' to the interconnecting terminal 6. In fixing the electric wires W1 and W2 to the connector terminal 1, the core wire 8 of the electric wire W1 and the core wire 8' of the electric wire W2 are inserted into the core wire-fixing barrel 4 and the coating film 9 of the electric wire W1 and the coating film 9' of the electric wire W2 are inserted into the coating film-fixing barrel 5. Then, the crimper 12 is moved downwardly to deform the barrels 4 and 5 and fix the core wires 8 and 8' to the core wire-fixing barrel 4 and coating films 9 and 9' to the coating film-fixing barrel 5.
As a result, the core wire 8 and the core wire 8' are connected with the connector terminal 1 or the interconnecting terminal 6, respectively. The conventional connector terminal 1 or the inter-connecting terminal 6 has a problem in that oxide film formed on the surface of the core wires 8 and 8' acts as a contact resistance in connecting the core wires 8 and 8' with the connector terminal 1 or the inter-connecting terminal 6.
In order to solve this problem, as shown in FIGS. 11 and 13, a plurality of serrations 13 is formed on the inner surface of the bottom of the core wire-fixing barrels 4 and 7 and that of the side walls thereof so as to shear and remove the oxide film from the core wires 8 and 8' by means of edges 13a of the serrations 13. This construction is disclosed in examined Japanese Utility Model Publication No. 34-11265.
However, as shown in FIGS. 12 and 14, the above-described construction is not effective for removing the oxide film from the core wires in fixing two or more core wires the barrels 4 and 7.
That is, as shown in FIG. 17, the core wire 8' disposed in the lower space of each of the barrels 4 and 7 contacts the serrations 13 formed on the bottom thereof in a large area, but the core wire 8 mainly contacts the serrations 13 formed on upper portions of the side walls of the barrels 4 and 7. Therefore, the core wire 8 contacts the serrations 13 in a small area. In addition, the core wires 8 and 8' disposed along the boundary (X) between the electric wires W1 and W2 do not contact the serrations 13. Accordingly, the oxide film is not removed therefrom along the boundary (X). That is, there is a possibility that the core wires 8 and 8' are not connected electrically.
As apparent from the above description, according to the above-described construction, the electric wires W1 and W2 are not electrically connected with each other because of the above-described reason.
In recent years, the operation of an automobile has been electronically controlled and hence micro-current circuits have been increasingly used and large current circuits generate a great amount of heat due to the use of a large capacity synchronous generator. In this situation, there are strong demands for the drop of the contact resistance between the core wires and the terminal and between the wires.